ABSTRACT
IN CONSIDERING separately the influence of the cytoplasm on the genes, by way of activation and inhibition, which was dealt with in the last chapter, and the influence of the genes on the cytoplasm by the production of substances active in development, we have made a distinction which, however convenient, is to some extent artificial. It will be shown later that in all probability the substances produced by genes at an early stage of development are themselves capable of affecting the levels of gene activity at later stages. The gene-cytoplasm complex is a single system, between the parts of which reciprocal interactions occur. But it is easier to discuss the individual steps in such circular reactions separately at first, and to try to put them together again later.
